Checkpatch reports: CHECK: struct mutex definition without comment.
Fix this by documenting what rx_mutex struct is used for in pi433 driver.
Signed-off-by: Paulo Miguel Almeida <[email protected]>
---
v2: ellaborate on reasons why the mutex lock is used in the driver (Req: Greg k-h)
v1: https://lore.kernel.org/lkml/[email protected]/
---
drivers/staging/pi433/pi433_if.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/staging/pi433/pi433_if.c b/drivers/staging/pi433/pi433_if.c
index 29bd37669059..1cd3d5f2df2a 100644
--- a/drivers/staging/pi433/pi433_if.c
+++ b/drivers/staging/pi433/pi433_if.c
@@ -92,6 +92,17 @@ struct pi433_device {
u32 rx_bytes_to_drop;
u32 rx_bytes_dropped;
unsigned int rx_position;
+ /*
+ * rx_lock is used to avoid race-conditions that can be triggered from userspace.
+ *
+ * For instance, if a program in userspace is reading the char device
+ * allocated in this module then another program won't be able to change RX
+ * configuration of the RF69 hardware module via ioctl and vice versa.
+ *
+ * utilization summary:
+ * - pi433_read: blocks are read until rx read something (up to the buffer size)
+ * - pi433_ioctl: during pending read request, change of config not allowed
+ */
struct mutex rx_lock;
wait_queue_head_t rx_wait_queue;
--
2.25.4
On Thu, Dec 23, 2021 at 10:56:15AM +1300, Paulo Miguel Almeida wrote:
> Checkpatch reports: CHECK: struct mutex definition without comment.
> Fix this by documenting what rx_mutex struct is used for in pi433 driver.
>
> Signed-off-by: Paulo Miguel Almeida <[email protected]>
> ---
> v2: ellaborate on reasons why the mutex lock is used in the driver (Req: Greg k-h)
> v1: https://lore.kernel.org/lkml/[email protected]/
> ---
> drivers/staging/pi433/pi433_if.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/staging/pi433/pi433_if.c b/drivers/staging/pi433/pi433_if.c
> index 29bd37669059..1cd3d5f2df2a 100644
> --- a/drivers/staging/pi433/pi433_if.c
> +++ b/drivers/staging/pi433/pi433_if.c
> @@ -92,6 +92,17 @@ struct pi433_device {
> u32 rx_bytes_to_drop;
> u32 rx_bytes_dropped;
> unsigned int rx_position;
> + /*
> + * rx_lock is used to avoid race-conditions that can be triggered from userspace.
> + *
> + * For instance, if a program in userspace is reading the char device
> + * allocated in this module then another program won't be able to change RX
> + * configuration of the RF69 hardware module via ioctl and vice versa.
> + *
> + * utilization summary:
> + * - pi433_read: blocks are read until rx read something (up to the buffer size)
> + * - pi433_ioctl: during pending read request, change of config not allowed
> + */
This is nice, but way too specific, and will quickly get out-of-date.
How about something simple like:
/* Protects all rx_* variable accesses */
thanks,
greg k-h
On Thu, Dec 30, 2021 at 11:56:33AM +0100, Greg KH wrote:
> On Thu, Dec 23, 2021 at 10:56:15AM +1300, Paulo Miguel Almeida wrote:
> > + /*
> > + * rx_lock is used to avoid race-conditions that can be triggered from userspace.
> > + *
> > + * For instance, if a program in userspace is reading the char device
> > + * allocated in this module then another program won't be able to change RX
> > + * configuration of the RF69 hardware module via ioctl and vice versa.
> > + *
> > + * utilization summary:
> > + * - pi433_read: blocks are read until rx read something (up to the buffer size)
> > + * - pi433_ioctl: during pending read request, change of config not allowed
> > + */
>
> This is nice, but way too specific, and will quickly get out-of-date.
>
> How about something simple like:
> /* Protects all rx_* variable accesses */
>
I see your point. I will send a new version of this patch with your
sugestion. Thanks for guidance.
thanks,
Paulo A.